Move main window to EtApplicationWindow object
Pass the main window to actions as user data
Move log area to EtLogArea object
Move playlist window to EtPlaylistDialog object
Move load filenames dialog to EtLoadFilesDialog
Move file search dialog to EtSearchDialog object
Move preferences dialog to EtPreferencesDialog
Move CDDB dialog to EtCDDBDialog object
Move scan dialog to EtScanDialog object
Replace strncat() with g_string_append()
Move select and unselect actions to main window
Move file selection actions to EtApplicationWindow
Set a rough initial window size and pane positions
Remove bogus conditional check

Found with Coverity (CID 1163350).
Remove a bogus sign check

Found with Coverity (CID 1163351).
Use g_format_size() instead of custom code

Replace Convert_Size() and Convert_Size_1() with g_format_size() to
avoid potential invalid memory accesses.

Found with Coverity (CID 1163338 and CID 1163339).